Study On Related Genes Affecting MOET Of Sheep

The technique of MOET (Multiple Ovulation and Embryo Transfer) in sheep has been investigated for years, but the effects have not been very stable for many factors. Molecular marker-assisted selection may be required to increase selection efficiency. The mutation (A746G) in the highly conserved intracellular kinase signaling domain of the BMPR-IB receptor was found to be associated fully with the hyperprolificacy phenotype of Booroola Merino ewes. FSH receptor (FSHR) gene is important to reproduction in mammals.The interaction between follicle-stimulating hormone (FSH) and FSH receptor (FSHR) is essential for normal oogenesis and spermatogenesis. Bone morphogenetic protein receptor-IB gene (BMPR-IB) and FSH receptor gene were studied as candidate genes. Seven sheep breeds, small tail han sheep and its crosses, Northeastern Half-fuzz sheep, Australian Merino sheep, German Mutton Merino sheep, Suffork sheep, Texel sheep and Charolais sheep, were used in this study. Single nucleotide polymorphism (SNP) were detected in these sheep breeds by PCR-RFLP and PCR-SSCP. The objective of the present study was to identify polymorphisms and Hyline layer for population genetic analysis, in trial population for evaluating correlation between BMPR-IB gene and FSHR gene polymorphisms and indexes of MOET in sheep. The results were as followings:1. The mutation (A746G) of the BMPR-IB gene was detected in the seven breeds. Population genetic analysis in different breeds showed that: the genotype frequency was different significantly among different sheep breeds (P<0.01).2. Sheep carrying B allele were able to ovulate more ova than non-gene carriers on the condition of spontaneous ovulation (P<0.01), and ovulating at a smaller diameter (P<0.05).3. There were significant correlation between different genotypes of BMPR-IB gene, of which pregnancy rates after frozen embryo transferred were different. Pregnancy rate of BB genotype sheep was significantly higher than that of the other two genotypes; The pregnancy rate of BB genotype sheep was 66.67% with respect to frozen embryo closely that of fresh embryo. However, the results of this study showed that the mutation of BMPR-IB gene appeared to positively affect both ova number and pregnancy process, which suggests that BMPR-IB gene plays an important role in the regulation of sheep prolificacy. So we may select ideal genotype sheep by PCR-RFLP as recipient. It provides a new approach to improve pregnancy rate of Embryo Transfer.4. After the whole exon 10 was detected by PCR-SSCP, SNPs were not found to be similar to those of human being and cattle.5. Three SNPs were found in 5′flanking region of sheep FSHR gene. In primer FSHRP1 product, we detected C-528T mutation and the genotypes frequency differed among different sheep breeds (P<0.05). In primer FSHRP2 product, we detected C-629T and T-681C mutation, the...